const regex = /(\d{4}.\d{3}.\d{3}) (\S+) (\S+) (\S+) (\S+) (\S+)\n(.+)\nHS\.code: (\S+) Country of origin: (\S+)\nEAN: (\S+)/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(\\d{4}.\\d{3}.\\d{3}) (\\S+) (\\S+) (\\S+) (\\S+) (\\S+)\\n(.+)\\nHS\\.code: (\\S+) Country of origin: (\\S+)\\nEAN: (\\S+)', 'gm')
const str = `"11 4149.310.025 000 1 37,78 1 37,78
PISTON
HS.code: 87084099 Country of origin: EU/DE
EAN: 2050000141478
21 0734.401.251 000 4 3,05 1 12,20
PISTON RING
HS.code: 73182100 Country of origin: JP
EAN: 2050000026638"`;
const subst = `: $1 $2 $3 $4 $5 $6 $7 $8 $9 $10\n`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions